Metaplastic carcinoma of the breast: Imaging and pathological features

Abstract

Abstract. Metaplastic carcinoma of the breast is a rare form of breast cancer. The aim of the present study was to investigate the imaging and pathological features of metaplastic carcinoma. The features identified on mammography and sonography were retrospectively reviewed in 13 women with metaplastic carcinoma of the breast. The results from the mammographs and sonographs were additionally evaluated using immunohistochemical staining for the expression of the estrogen receptor (ER) and progesterone receptor (PR), receptor tyrosine-protein kinase erbB-2 (CerbB-2) and P53. The most common features observed in the mammographs were as follows: Irregular and oval shaped masses, 53.8 and 46.2%, respectively; spiculated and circumscribed margins, each 30.8%; and high and marginally high density masses, 69.2 and 30.8%, respectively. The most common sonography features observed were as follows: Hypoechoic masses, 84.6%; complex echogenicity, 76.9%; irregular, round and oval shaped masses, 69.2, 30.8 and 30.8%, respectively; indistinct and circumscribed margins, 53.8 and 46.2%, respectively; an abundant blood flow, 53.8%; and posterior acoustic enhancement, 61.5%. The immunohistochemical (IHC) profile for 13 patients demonstrated that ER was not expressed in 100% of patients, PR and CerbB-2 were not present in 92.3% of patients, and P53 was present in 63.6% of patients. Therefore, metaplastic carcinoma of the breast exhibits more benign IHC features compared with invasive ductal carcinoma. In addition, it may be challenging to diagnose patients that do not possess posterior acoustic enhancement or express hormone receptors from other types of breast cancer. IntroductionMetaplastic carcinoma of the breast is a rare form of breast cancer and possesses a poorer prognosis than other common types of breast cancer (1). Metaplastic carcinoma exhibits the metaplastic transformation of glandular epithelium to squamous epithelium and mesenchymal tissue, and accounts for <5% of all breast cancers (2) and may contain glandular and non-glandular components with mixed epithelial and mesenchymal tissue. Involvement of the axillary lymph node is rare, with hematogenous metastasis occurring more commonly in cases of metaplastic carcinoma (1,3). Metaplastic carcinoma demonstrates a poorer prognosis and a higher risk of recurrence compared with other types of breast cancer (3). It typically presents as triple negative, therefore the effects of hormonotherapy are limited (3,4). Due to the heterogeneity of metaplastic carcinoma and its increased complexity compared with more common types of breast cancer, mixed chemotherapy regimens and dose schedules may be more effective and appropriate (2). Due to the distinction in surgical treatment and chemotherapy between metaplastic carcinoma and other breast cancers, it is particularly important to diagnose the tumor correctly (2). Metaplastic carcinoma demonstrates a number of benign features similar to invasive ductal carcinoma in mammograms and sonograms, and subsequently may be misdiagnosed as ...

Imaging Findings of Metaplastic Carcinoma of the Breast with Pathologic Correlation

“…However, MCB have been described as presenting at a younger age, with larger tumor size and a more rapid growth than the more prevalent forms of breast cancer [ 1 2 8 10 ]. Nevertheless, some authors have found that MCB can be more common in women older than 50 years, such as in this series that has a median age of 65 years at presentation [ 4 13 ].…”

“…The most frequent clinical finding of MCB is a palpable breast mass, similar to the more common forms of breast cancer [ 1 2 4 ]. However, MCB have been described as presenting at a younger age, with larger tumor size and a more rapid growth than the more prevalent forms of breast cancer [ 1 2 8 10 ].…”

“…As seen in this study, it usually presents as a triple negative or basal-like breast cancer, being less associated to expression of estrogen, progesterone and HER2 receptors. These characteristics further reduce the outcome of MCB patients by limiting treatment options [ 1 3 4 10 ].…”

“…Metaplastic carcinoma of the breast (MCB) is a rare and aggressive form of breast cancer, representing less than 1% to 5% of cases [ 1 2 3 4 ]. It should be distinguished from invasive ductal carcinoma, because MCB has a worse prognosis, and from breast sarcoma, because the treatment approach is different [ 5 6 ].…”

Rare case of metaplastic breast cancer in a man

“…According to WHO classification 2012, MBCs are classified as metaplastic carcinoma of no special type, low-grade adenosquamous carcinoma, fibromatosis like carcinoma, squamous cell carcinoma, spindle cell carcinoma, metaplastic carcinoma with mesenchymal differentiation (chondroid differentiation, osseous differentiation), mixed metaplastic carcinoma and myoepithelial carcinoma 12–14. The most common type of MBC is squamous cell carcinoma accounting for 0.5%–3.7% of all the breast cancers followed by spindle cell carcinoma and matrix-producing carcinoma 14. The main pathological feature of this cancer is epithelial and mesenchymal transition 15 16.…”